I don't understand the mindset, but maybe that's because I've never actually been offered that much money (studies show that money tends to accentuate our preexisting biases). But I mean what sort of comparative outcomes could you have been looking at to make you turn down $20 million? Say the company tripled in value and you sold for $60 million...did you have plans of what you needed to do with 60 million that you could not do with 20 million?
I'm sure you've done enough beating yourself up here and I'm not trying to insult you, I'm honestly curious as to what your thought process looked like at the time. That way if I ever have the same thoughts I'll know of at least one example where they obviously weren't justified.
I didn't have plans for $20 million, ephemeral or real. I didn't have a number at all. But I think that's symptomatic of the problem. The problem seems to lie in the "suspension of reality" that exists for many entrepreneurial endeavors. I wasn't "in it for the money" when I started. I was trying to "change the world". I hadn't finished changing the world yet, so a buyout was only money to me. The correction of course, is to understand that your business is for the purpose of making money first and other things second. But its hard for most inventors to get motivated and work so hard for money. Its much easier to do it for a grander purpose. The problem is this "suspension of reality" bubble is hard to break once you've made it past the initial successes.
Do I have regrets? A little, but not overwhelmingly so. I have plenty in life to be thankful for. I put the lost money in the category of "yet another multi-million-dollar-MBA" I've earned ;).
I'm sure you've done enough beating yourself up here and I'm not trying to insult you, I'm honestly curious as to what your thought process looked like at the time. That way if I ever have the same thoughts I'll know of at least one example where they obviously weren't justified.